Gender Confusion

I wonder if there is a course somewhere on gender identification. We mistook our little boy kitten, Wooper, for a girl and named him/her Woopka. 

Once we realized our mistake, we understood why he had imprinted on our naughty male cat, Intrepid, rather than on Simone, the gentle lady for whom we had adopted Woopka as a companion. We brought Woopka back from the vet because she/he intrigued us with her/his brazenness. For example, one morning he/she  deliberately grabbed the trash bag, carefully dumped all the trash on the floor, and pranced off, holding the plastic bag in his mouth and his head high. Audacious little thing!

So, seeing that we had a little boy, we changed his name to Wooper. For two months, he pranced, fisticuffed, and head butted with the other two boy cats, Intrepid and Murjan. Where Simone will hang back during feedings, he trots right up in line with the other boys.

The time came to have him neutered. That was yesterday. We took him in to be neutered. The vet called to say he could not neuter him but rather needed to spay him/her. Wooper (or Pooper, as the vet assistant accidentally wrote down on Wooper's ID card), it turned out, is, after all, a girl.

This is so confusing. I better go check my kids. I thought we had two boys and two girls. Now, I am not so sure!